Reverse a linked list - https://www.hackerrank.com/challenges/reverse-a-linked-list

ReverseLinkedList.cpp

/*
  Reverse a linked list and return pointer to the head
  The input list will have at least one element  
  Node is defined as 
  struct Node
  {
     int data;
     struct Node *next;
  }
*/
Node* Reverse(Node *head)
{
  if(head == NULL) return NULL;
  Node *current = head;
  Node *prev = NULL;
  Node *next = NULL;
    while(current != NULL) {
        next = current->next;
        current->next = prev;
        prev = current;
        current = next;
    }
    head = prev;
  return head;
}